Angle Grinder Arm Cover Structure for Support Arm Rigidity
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Solution Overview
Problem
Hand-held cut-off machines with compact and delicate support arms face challenges in withstanding high forces during operation, leading to potential damage and reduced stability and rigidity.
Innovation Solution
The use of a metal arm cover with fastening elements arranged above the output axis of rotation allows forces to be diverted into the arm cover, reducing the load on the support arm and enhancing its ability to handle high forces without damage, while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the support arm is designed to be compact and delicate to achieve increased cutting depths, then the cutting depth is improved, but the stability and rigidity of the support arm deteriorates
Solution Approach 1:
The support arm is divided into multiple segments or sections, allowing the distal end to be compact for increased cutting depth while the proximal end maintains structural integrity. The arm cover is also segmented with reinforcement elements strategically positioned to provide localized strengthening without compromising overall compactness.
Solution Approach 2:
The support arm combines materials with different properties - using lighter, more compact materials in regions where weight reduction is critical while incorporating reinforcement elements or composite structures in regions requiring higher strength and rigidity to withstand operational forces.
2Length of moving object
If the support arm is made compact and delicate near its second end, then the cutting depth capability is improved, but the load-bearing capacity deteriorates
Solution Approach 1:
The support arm features non-uniform structural properties along its length - the distal end is optimized for compactness and cutting depth with a more delicate structure, while the proximal end and critical load-bearing regions incorporate reinforcement elements, thicker walls, or structural features that increase strength where forces are highest.
Solution Approach 2:
The arm cover is positioned in three-dimensional space above the second plane (above the output rotational axis and drive rotational axis), utilizing vertical space to provide structural reinforcement without increasing the horizontal footprint or compromising the compact distal end design.
3Productivity
If forces are transferred directly to the support arm via the spindle and bearing elements, then the cutting performance is improved, but the risk of support arm damage increases
Solution Approach 1:
The arm cover serves as an intermediary structural element between the cutting spindle and the support arm. It provides an additional load path and force distribution mechanism, transferring forces from the cutting operation through the arm cover to the support arm, thereby reducing concentrated loads on the support arm while maintaining cutting performance.
4Weight of moving object
If the arm cover is made of plastic material, then the weight is reduced, but the ability to transmit forces without damage deteriorates
Solution Approach 1:
The arm cover uses composite construction or composite materials - combining plastic base material with reinforcing elements such as metal inserts, fibers, or structural features that provide enhanced strength and force transmission capability while maintaining lightweight characteristics of the plastic material.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively distributes high forces across the arm cover, enhancing the support arm's stability and rigidity, reducing the risk of damage and maintaining a minimal impact on cutting depth.
Implementation Method 1
An arm cover made of a metal material has the advantage over conventional plastic arm covers that, due to the higher modulus of elasticity, forces generated can be transmitted by the arm cover without damaging the arm cover.
Data Source
Figure 1A~1B
Figure 2~3
AI summary
Hand-held angle grinder comprising a cutting disc, a motor housing with a drive unit and a boom with a support arm and an arm cover, which is attached to the support arm via several fastening elements.